The present invention relates to a burner for gaseous or liquid fuels. The known burners normally include a cooled hollow casing and a cooled hollow jacket surrounding the casing so that concentrically positioned annular channels for feeding fuel and oxygen-containing gas to a burner nozzle are formed therein.
The conventional burners are preferably utilized in the industry as heating burners for gasification installations operating under pressure. The burner of the conventional type is ignited when the pressureless condition occurs within the interior of the gasifier but thereafter, in operation, the burner must withstand internal pressures occured in the gasifier which can reach 15 bars. The ratio between the internal pressures within the gasifier and the inlet pressures of the burners must be set up during the entire heating process so as to secure stable supercritical outlet velocities of the combustible fluids discharged from the nozzle of the burner.
It has been established that various thermal expansions occured in the inner hollow casing and the jacket surrounding the same may result in mutual displacement of these elements against one another in the region of the burner nozzle which can lead to increasing of the nozzle gap or increasing of the width of the slots between the elements forming the nozzle gap of the burner. This leads to reducing outlet velocities of combustible fluids discharged from the burner nozzle which velocities fall below the required supercritical velocities. The result of this is a possibility of backflash ignition which may cause damage of the burners.
It is therefore desirable to maintain the outlet velocities of the combustible mixture discharged from the burner nozzle at substantially permanent optimal level.